1. Field of the Invention
The present invention relates to a panel assembly for an electronic keyboard musical instrument. The panel assembly is disposed over a substantially entire width in a direction in which keys are arranged (i.e., in the right and left direction of a keyboard) to thereby cover electronic circuits or the like contained inside the electronic keyboard musical instrument.
2. Description of the Related Art
Conventionally, a panel for use in an electronic keyboard musical instrument is ordinarily formed in the following shape. Namely, it extends from the back of a keyboard at an upward inclination toward the rear of the electronic keyboard musical instrument, and thereafter forms a horizontal portion. It further extends substantially vertically downward to thereby form a rear wall of the electronic keyboard musical instrument. The panel covers electronic circuits and mechanisms such as an action (i.e., a mechanism to operatively function the keys), or the like of the electronic keyboard musical instrument. In this manner, the electronic circuits or the like are prevented from being exposed to the outside. Further, in that inclined portion of the panel which extends from the back of the keyboard at an upward inclination, there are disposed switches such as for varying the tone and indicators such as light-emitting diodes (LED's) or the like. This kind of panel must be provided with the inclined portion, the horizontal portion, and the rear wall portion in the back and forth direction (i.e., in a direction perpendicular to the direction in which the keys are arranged). Therefore, the shape of the panel varies in a complex manner in this direction. On the other hand, the shape of the panel in the right and left direction (i.e., in the direction in which the keys are arranged) does not vary but remains constant. Therefore, the panel is integrally formed as a single piece of member by using an extruded material which is formed by extruding a metallic material such as aluminum or the like in the right and left direction of the keyboard.
However, when the electronic circuits become complicated and large in size, or when the action in the keyboard become large in size, the width of the electronic keyboard musical instrument in the back and forth direction becomes large. It follows that the width of the panel in the back and forth direction, i.e., in the direction perpendicular to the one in which the panel is extruded, becomes large. If the above-described width of panel becomes large, metallic dies for use in extruding process also become large in size and expensive. In addition, the extruding force must be increased. As a result, a large size of extruding apparatus must be used. Further, in case the panel is subjected to surface treatment for a decorative purpose, the surface treatment of the front portion of the panel is sometimes made different from that of the rear portion thereof. If such different surface treatments are made on the integrally formed single piece of panel, that portion of the panel which is not subjected to surface treatment must be covered by a masking material to prevent it from being surface-treated. Another masking must also be made on the already surface-treated portion when the remaining portion is surface-treated. In this manner, the surface treatments take a lot of working steps and manpower.